String.charCodeAt Max Length

Question

Take this code:

var charCode = unkownVariable.charCodeAt(0);

What is the max length that charCode can be? All my tests turned out as 2 character (2 digits). Will it ever be longer?

Felix Kling · Accepted Answer · 2013-03-21T17:10:51.667

4

From the specification:

Returns a Number (a nonnegative integer less than 2¹⁶) representing the code unit value of the character at position pos in the String resulting from converting this object to a String. If there is no character at that position, the result is NaN.

So, 2¹⁶ - 1 is the maximum value, which is 65535.

edited Mar 21 '13 at 17:10

answered Mar 21 '13 at 17:03

Felix Kling

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Interesting. So the smallest, single-byte representation of the highest character code (with native JS decode support) would be: `1ekf` (`(65535).toString(36)`) – Nathan J.B. Mar 21 '13 at 17:19
Is there any way, we can access this 2^16 - 1 (the maximum value, which is 65535) ? For example, for numbers we have Number.MAX_VALUE. Thanks in advance. – Rashmi Jul 13 '22 at 08:13
@Rashmi: I'm not aware of a built-in constant representing that value, but if you know it then you can create your own constant. – Felix Kling Jul 13 '22 at 09:03

CWSpear · Answer 2 · 2013-03-21T17:18:25.667

1

Short answer: yes.

var unkownVariable = 'test';
var charCode = unkownVariable.charCodeAt(0);
console.log(charCode); // 116

There are 16 bits used to display characters (there are different languages and charsets to consider), so the response theoretically could be anywhere between 0 and 65536 (2^16).

edited Mar 21 '13 at 17:18

answered Mar 21 '13 at 17:03

CWSpear

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score 1 · Answer 3 · answered Mar 21 '13 at 17:05

1

MDN says

Note that charCodeAt will always return a value that is less than 65,536.

https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/String/charCodeAt

answered Mar 21 '13 at 17:05

Aaron Kurtzhals

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String.charCodeAt Max Length

3 Answers3